36 BULLETIN 125, rXlTED STATES XATIOXAL MUSEUM. 



Genus MEMBRENDOECIUM Canu and Bassler, 1917. 



(For description see Bulletin 106. U. S. National Museum, p. 119.) 

 MEMBRENDOECIUM PARVICAPITATUM, new species. 



Plate 12, iigs. 1, 2. 



Description. — The zoarium encrusts shells. The zooecia are distinct, separated 

 by a deep furrow, elongated, elliptical; the mural rim is thin and rounded. The 

 opesium is of the same form as the zooecium. The ovicell is very small, transverse, 

 endozooecial, scarcely salient. A verj- small triangular avicularium appears some- 

 times between the zooecia. 



^ . [Ao= 0.36 mm. „ . fi2= 0.44 mm. 



Measurements.-Opesiai^ ^^ ^ ^ 26 mm. ^^^^'^'^l fe = 0. 32-0. 34 mm. 



Variations. — The measurements are very irregular. The regeneration of the 

 polypide is very frequent and our figure shows an ovarian zooecium replaced by an 

 ordinary one. The mural rim is very finely granulated. The small avicularium is 

 quite rare. According to the rule in this genus it is deprived of pivot. 



All of the resemblances of this species are with Callopora guemei, Jullien, 1904, 

 and it is close to this latter species that we would have to refer the present new species 

 in case additional specimens should show that the small distal elevation of the mural 

 rim is not an endozooecial ovicell. 



Occurrence. — Miocene (Choctowhatchee marl) ; Jackson Bluff, Ocldocknee River 

 25 miles southwest of Tallahassee, Florida (rare). Miocene (Bowden marl) : Bowden,. 

 Jamaica (rare). 



Holotype and paratype. —Cat. Nos. 68439, 68440, U.S.N.M. 



• MEMBRENDOECIUM GRANDE, new species. 



Plate 11. figs. 10-12. 



Description. — The zoarium incrusts shells. The zooecia are distinct, separated 

 by a furrow of little depth, elongated, large, irregular; the mural rim is thin, bevelled, 

 with a sharp termen. The opesium is large, entire, of the same form as the zooecium. 

 The ovicell is endozooecial, small, little salient, transverse. 



Measurements.-0^esi4]' = ^^ f/^^- Zooeciap/=^- JO ^- 



|/o = 0. 40 mm. [^2=0. 50 mm. 



Affinities. — This species has the aspect of Membranipora irregularis Manzoni, 

 1875, of the Italian Pliocene, but differs in its larger dimensions {Lz = 0. 70 and not 

 0. 60 mm.) and in the absence of a distal thickening in the form of a turret. It has 

 also the general aspect of the recent Membranipora irregularis Smitt, 1872; but we 

 have noted (see p. 142 of Bulletin 106, U. S. National Museum) that the latter is a 

 characteristic Alderina; there is therefore a fundamental difference in the ovicell. 



Occurrence.— Miocene (Duplin marl): Wilmington, North Carolina (very rare). 

 Pliocene (Waccamaw marl) : Waccamaw River, Horry County, South Carolma (rare). 

 Recent : Various localities in the Gulf of Mexico. 



Cotypes.—Cnt. Nos. 68441,68442, U.S.N.M. 



